This invention relates generally to the field of fans and, more particularly, to portable fans of the type used in firefighting applications by the use of positive pressure ventilation to help the firefighter both clear smoke from his path and fight the fire.
Positive pressure ventilation is a firefighting technique for removing heat and smoke from a fire area within a building or the like wherein clear air is directed into the building to produce a positive pressure therein by using fans, or blowers. This technique is becoming well known in the art and involves, by way of example, positioning the fan in or near a ground floor doorway of a house having a fire therein and breaking open a window at a desirable location on the other side of the fire, such as on the second floor. The fan is operated to blow air into the house to create what is called a "positive pressure" inside the house (typically a couple inches of water pressure) which pushes the smoke out. By the proper selection of the location of the exit opening and the direction of air flow from the fan, the clear air will flow from the doorway across the fire area to move smoke and heat away from the fire area so that it rises up and out of the house and away from the firefighters through the second floor opening provided.
There are two types of blowers in use today for this type of firefighting application; namely, electric blowers and gasoline-powered blowers. Electric blowers have the disadvantage that for portable construction the higher horsepower motors are too heavy and cannot provide the high power requirements for many applications. Further, the higher current required may not be available in an emergency situation. Also, electric blowers normally are limited in speed to 3600 RPM. Gasoline-powered blowers have the disadvantages that they are noisy, heavy, and introduce deadly carbon monoxide inside the structure where the fire is located.
In copending application Ser. No. 242,494, filed Sept. 12, 1988, and assigned to Hale Fire Pump Company, there is shown a fan system for firefighting by the use of positive pressure ventilation which obviates the problems of electric and gasoline-powered blowers in use today by providing a clean operation and by providing sufficient power with light weight and portability for firefighting applications.
It is the general object of this invention to provide a water driven fan of the indicated type which is an improvement over that disclosed in said copending application.
In furtherance of the general object of the invention, there is provided a portable fan driven by a water turbine capable of delivering air volume at more than 30,000 cubic feet per minute. The water driven fan in accordance with the invention requires no ignition, produces no exhaust, uses no electricity and eliminates the danger of sparking and the introduction of carbon monoxide into a building. Furthermore, the design in accordance with the invention can move a large amount of air in the safest way possible. Further, the design in accordance with the invention achieves a balance between efficiency and safety while offering the best performance with the lightest weight. The fan in accordance with the invention can be powered from any pumper with a tank, or from a hydrant, and can also be operated remotely from a fire truck. An actual embodiment comprises twelve polyamide fan blades, with the fan being 30 inches in diameter and being capable of providing sufficient pressure to ventilate several rooms simultaneously. This actual embodiment is lightweight and portable, weighing only 75 pounds and measuring only 35 inches high, 35 inches wide and 21 inches long. Moreover, there is provided a water mist means which provides exposure protection for the firefighter, decreases the energy of the fire, improves the heat transfer ability of the air and replaces oxygen with water vapor in the immediate vicinity of the fire.
Another feature of the invention is a novel inlet valve design whereby the inlet valve for the water is integrated into the main body of the turbine, and the valve member has a balanced action so that it is easy to open and move throughtout the flow controlling positions thereof.
Another feature of the invention is the arrangement of the inlet and outlet of the water flow to the turbine such that the inlet and outlet connections project in the same direction and opposite to the direction of the air flow. This arrangement allows the hoses to be positioned such that they form two trust absorbing legs of a tripod support for the unit during operation.
Another feature of the invention is the compact design of the water turbine which has a relatively small diameter. This small diameter construction reduces the weight of the unit and minimizes the blockage of air flow to the upstream side of the fan which results in a smoother and greater air flow.
Another feature of the invention is the provision of a novel carrying handle design whereby a single bar is configured to provide means for use in tilting or aiming the unit easily, easy access to handle portions for carrying or wheeling the unit, and safety protection against damage to the unit.
Another feature of the invention is the provision of a tilting support for the fan and turbine unit and means for locking the unit at a desired angular position about a pivotal support for the same to facilitate directing the air flow, for example, toward the center of the door opening.
Another feature of the invention is the provision of a novel "built-in" flow indicator design to provide an indication to the operator of the volume of air flow of the unit.
Another feature of the invention is the provision of a novel construction and arrangement of spray nozzles for introducing water into the air stream.
Other features of the invention relate to design safety of the unit. To this end, there are provided both plastic blades and a plastic shroud, which prevents the possibility of sparks even if rubbing should occur. Moreover, the turbine is constructed of a non-ferrous material which also prevents the possibility of sparks.
There is also disclosed a novel method and system for supplying recirculating water at high pressure in a closed loop system for the operation of a water driven fan or the like.